Nail Polishing Device

ABSTRACT

The nail polishing device  1000  has case member  100.  A first shaft member  410  and a second shaft member  420  are provided inside of the case member and a first rotation member  210  and a second rotation member  220  are mounted on the first shaft member and the second shaft member. The lower surface of the case member is recessed inwardly in its middle part to form a space  170  and a cushion member  70  is in the space. A polishing sheet  200  is wound around and through the first rotation member and the second rotation member. The polishing sheet is discharged out through opening  88  in the front of the case member and extends into a passage slot  180  on the lower surface of the case member and then, is wound around the first rotation member. A rotation handle  80  for rotating the first rotation member is provided and a holder  60  for holding the discharged polishing sheet  200   c  is arranged at the opening in the front of the case member.

BACKGROUND

The present invention relates to a nail polishing device for polishing nails or toenails and, more particularly, to a nail polishing device in which a polishing sheet for polishing nails or toenails is partly discharged to be used and the polishing sheet can be replaced by new one after the whole parts of the polishing sheet are all used.

Various applications have been filed in connection with nail polishing devices for polishing nails to trim or make them glossy. Method for producing a buffer for trimming nails the usage life of which is long (Patent No. 10-0367728-0000), a file for polishing nails and method for producing the same (Patent Laid Open Publication No. 2003-0000879), a tool for trimming nails (Patent No. 10-0515385-0000) and nail-polishing and glossy device (Utility Model Registration No. 20-0440465-0000) are some examples.

These conventional nail polishing devices have a body part in the form of a plate or a hexahedron and a polishing sheet attached thereto. The polishing sheet is a sponge sheet or a fabric and polishing particles are adhered thereto.

A user holds the body part and rubs the nail or toenail with the polishing sheet to trim it or make it glossy.

The conventional nail polishing tool is formed by the body part to which the polishing sheet is attached as described. The user has some habits to holds the body part and the user uses mainly the same part so that the part of the polishing sheet is mainly worn out. Therefore, the nail polishing device is thrown away even though the whole parts of the polishing sheet are not used. When it is thrown away, the body part made from plastic or sponge is also thrown away as well as the polishing sheet and this is the waste of resource.

Accordingly, it is necessary to provide a nail polishing device in which all parts of the polishing sheet are uniformly used and the polishing sheet is discarded only when the polishing sheet is all used. The present invention satisfies this demand.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a nail polishing device in which all parts of the polishing sheet are uniformly used and the polishing sheet is discarded only when the polishing sheet is all used.

The present invention provides a nail polishing device comprising: a case member having an opening in its front and a passage slot on its lower surface; a cushion member disposed on the lower surface of the case member and between the opening of the case member and the passage slot of the case member; a polishing sheet wound around and through a first rotation member and a second rotation member inside of the case member, exposed to external around the opening and the passage slot of the case member and contacting the lower surface of the cushion member; and a rotation handle for rotating the first rotation member.

According to the present invention, it is preferable if the case member has two case members detachably assembled each other.

According to the present invention, it is preferable if the nail polishing device further comprises a holder member rotatably arranged at the opening of the case member to open or close the opening of the case member and having a projection part on its front face and a groove formed in front of the cushion member on the lower surface of the case member in which the projection part is engaged when the holding member rotates to close the opening of the case member.

According to the present invention, it is preferable if the lower surface of the case member recessed inwardly in its middle part to form space and the cushion member is disposed on the space.

According to the present invention, it is preferable if the nail polishing device further comprises a ratchet mechanism combined with the first rotation member for limiting rotation direction of the second rotation member to a direction that the polishing sheet is released, the ratchet mechanism including: a first gear integrally rotating with the first rotation member; a second gear engaged with the first gear and having a pawl on its bottom surface; a ratchet gear corresponding to the pawl formed on inner face of the case member; wherein, the second gear has a protrusion and the second rotation member has a centered through hole so that the protrusion of the second gear is inserted into the centered through hole of the second rotation member.

According to the present invention, it is preferable if the protrusion of the second gear has a plurality of vertical members spaced one other along circumferential direction.

According to the present invention, it is preferable if the nail polishing device further comprises a third gear having teeth along circumferential direction and a plurality of vertical parts extending downwardly and spaced one another along the circumferential direction; wherein, the vertical parts of the third gear is inserted into the centered through hole of the second rotation member and the vertical parts spaced one another on the bottom surface of the third gear are arranged in between the vertical members of the second gear spaced one another so that the rotation of the third gear and the rotation of the second gear are integrally connected with each other; and the holder member has an extension part extended towards the third gear and having a corresponding part corresponding to the shape of the teeth of the third gear at the end of the extension part so that when the holder member rotates to close the opening of the case member, the corresponding part correspondingly engages with the teeth of the third gear.

As described, the present invention provides the nail polishing device in which a part of the polishing sheet is discharged and used, and a new part of the polishing sheet is newly discharged out and used after the discharged part of the polishing sheet is used and when all parts of the polishing sheet are used, it can be replaced by new one.

Also, the present invention disposes the cushion member on the lower surface of the case member and the partly discharged polishing sheet contacts the cushion member as it is extended. The partly discharged polishing sheet is stably seated on the cushion member so that when holding the case member and rubbing the nail with the polishing sheet, the polishing sheet stably polishes the nail. Also, the polishing sheet is stably stayed at the cushion sheet because of the friction therewith and the soft polishing is possible because of the cushion from the cushion member.

Further, according to the present invention, the rotation handle is limited to rotate to one direction and the released polishing sheet is not wound again. This function is accomplished with two gears connected with each other. Especially, the rotation member around which the polishing sheet is wound is mounted on the gear on which the ratchet is equipped. Accordingly, space is used efficiently.

Further, the present invention provides the holder member holding the polishing sheet. The holder member has the projection part on its front face and the case member has the groove on its lower surface with which the projection part is engaged. When the holder member moves to close, the projection part is engaged with the groove and holds the polishing sheet more firmly.

Furthermore, according to the present invention, the holder member holds the rotation member around which the polishing sheet is wound and when the holder member is closed, the polishing sheet is held not to move so that the user can stably polish the nail or toenail.

Eventually, according to the present invention, the user can use the polishing sheet as much as it is used by discharging it as much and replace it by new one when the whole parts of the polishing sheet are all used, and stably polish the nail or toenail without shake.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are views showing appearance of a nail polishing device according to an embodiment of the present invention;

FIGS. 3 to 5 show exploded views of the nail polishing device according to the embodiment of the present invention;

FIG. 6 is a perspective view of a case member according to the embodiment of the present invention;

FIG. 7 is a view showing how to use the nail polishing device according to the embodiment of the present invention;

FIG. 8 is a view showing another embodiment of a holder member according to the present invention;

FIGS. 9 to 13 are views showing that the holder member according to the present invention prohibits the rotation of a rotation member.

DETAILED DESCRIPTION

The preferred embodiment of the present invention is described with reference to the attached drawings.

FIGS. 1 and 2 show appearance of a nail polishing device 1000 according to an embodiment of the present invention.

The nail polishing device 1000 has a case member 100 inside which a polishing sheet 200 is disposed as it is wound and a cushion member 70 is disposed at the lower surface of the case member 100. A part of the polishing sheet 200 c is discharged out to the external and contacts the lower surface of the cushion member 70.

A rotation handle 80 is provided in the case member 100 and a part of the polishing sheet 200 wound inside the case member is discharged out and extends below the cushion member 70 when the rotation handle 80 works.

In the front of the case member 100, a holder member 60 for pressing the polishing sheet 200 is rotatably arranged at an opening 88 in the front of the case member 100 and it can open or close the opening 88.

A nail-trimming member 40 for trimming nails by rubbing is provided in upper surface of the front of the case member 100.

The nail-trimming member 40 is a plate type metal member the surface of which is rough and it rubs the edge of the nail to trim it.

With reference to FIGS. 3 to 5, the case member 100 has a first case member 100 a and a second case member 100 b, both of which are detachably assembled each other. As described later, the used polishing sheet 200 can be replaced by new one after the first case member 100 a and the second case member 100 b are disassembled each other.

The first case member 100 a and second case member 100 b are symmetrical to each other and they are detachably assembled each other.

In this embodiment, a plurality of protrusions 61 are formed in the inner surface of the first case member 100 a and a plurality of protrusions 68 having holes are correspondingly formed in the inner surface of the second case member 100 b. The protrusions 61 are combined into the holes of the protrusions 68 so that the first case member 100 a and second case member 100 b are detachably combined with each other.

An opening 88 a is formed in the front of the first case member 100 a and the middle of the lower surface of the case member 100 a is recessed. That is, the lower surface of the case member 100 a has a first lower surface part 101 a, a second lower surface part 102 a and a third lower surface part 103 a along the opening 88 a of the front portion to the rear portion thereof, and the second lower surface part 102 a is recessed and a space 170 a is formed between the first lower surface part 101 a and the third lower surface part 103 a.

Also, a passage slot 180 a is formed transversely between the third lower surface part 103 a and the second lower surface part 102 a.

An opening 88 b corresponding to the opening 88 a of the first case member 100 a is formed in the second case member 100 b and the middle of lower surface of the second case member 100 b is recessed corresponding to the lower surface of the first case member 100 a. That is, the lower surface from the opening 88 b of the front to the rear has a first lower surface part 101 b, a second lower surface part 102 b and a third lower surface part 103 b and the second lower surface part 102 b is recessed and a space 170 b is formed between the first lower surface part 101 b and the third lower surface part 103 b.

Also, a passage slot 180 b to which the passage slot 180 a is extended is formed transversely between the third lower surface part 103 b and the second lower surface part 102 b.

The first, second and third lower surface parts 101 b, 102 b and 103 b of the second case member 100 b correspond to the first, second and third lower surface parts 101 a, 102 a and 103 a of the second case member 100 a. In this embodiment, the first, second and third lower surface parts 101 a, 102 a and 103 a of the first case member 100 a have seat parts 1011, 1012 and 1013 on which the first, second and third lower surface parts 101 b, 102 b and 103 b of the second case member 100 b are seated.

Accordingly, when the first case member 100 a and the second case member 100 b are put together, as shown in FIG. 6, the opening 88 is formed, a first, second and third lower surface parts 101, 102 and 103 are continuously formed to the rear of the opening 88, the second lower surface part 102 is recessed, a space 170 is formed between the first lower surface part 101 and the third lower surface part 103 and a passage slot 180 through which the polishing sheet passes is formed transversely between the third lower surface part 103 and the second lower surface part 101.

The cushion member 70 is disposed in the space 170 formed between the first lower surface part 101 and the third lower surface part 103.

According to the present embodiment, the cushion member 70 is attached to the second lower surface part 102 by means of adhesive, however, other attachment are possible. For example, a rail having grooves is provided in the space 170 and the cushion member 70 is inserted in the grooves.

The cushion member 70 is to contact a part of the polishing sheet 200 c released and discharged out from the wound polishing sheet 200 disposed inside the case member 100. When rubbing the nail (or toenail) with the part of the polishing sheet 200 c, friction is produced between the cushion member 70 and the part of the polishing sheet 200 c so that the cushion member 70 holds the part of the polishing sheet 200 c and gives cushion thereto. As a result, it is possible to polish the nail softly. The cushion member 70 can be made from silicone resin, sponge or rubber.

With reference to FIG. 4, a first shaft member 410 and a second shaft member 420 are provided inside of the second case member 100 b and a first rotation member 210 and a second rotation member 220 are mounted on the first shaft members 410 and the second shaft member 420, respectively.

In this embodiment, the polishing sheet 200 is wound around the second rotation member 220 and it is released and then wound around the first rotation member 210.

The first rotation member 210 has a connection member 219 connected to a rotation handle 80 outside the case member 100. The case member 100 a has an opening 244 corresponding to the first rotation member 210 through which the coupling part 89 of the rotation handle 80 is inserted and coupled to the connection member 219.

Accordingly, the polishing sheet 200 wound between the rotation members 210 and 220 keeps tension and if the rotation handle 80 rotates, the first rotation member 210 rotates and the second rotation member 220 follows to rotates so that the polishing sheet 200 wound around the second rotation member 220 is released or wound again according to the direction of the rotation.

In this embodiment, the polishing sheet 200 wound around the second rotation member 220 is released and extends in a way that it is discharged out through the opening 88 of the case member 100 as it is supported by a supporting portion 1016 of the first lower surface part 101 on the lower part of the opening 88, contacts the cushion member 70 and passes in through the passage slot 180 in the third lower surface part 103 and then it is wounded around the first rotation member 210. Accordingly, the polishing sheet 200 can keep the tension. (In the drawings, as described later, gears 218, 228 and 268 are additionally mounted and the second rotation member 220 is mounted on the gear 228. However, these can be excluded and as described above, the second rotation member 220 can be mounted on the shaft member 420.)

Meanwhile, although it is not shown, the polishing sheet 200 wound around the second rotation member 220 can be released and extends in a way that it is discharged out through the passage slot 180 on the lower surface part of the case member 100, contacts the cushion member 70 and passes in through the opening 88 as it is supported by a supporting portion 1016 on the lower part of the opening 88 and then it goes over the polishing sheet 200 wound around the second rotation member 220 and goes down the first rotation member 210 and is wound around the first rotation member 210.

According to the present invention, it is desirable if the first rotation member 210 is limited to rotate to the direction that the polishing sheet 200 wound around the second rotation member 220 is released and wound around the first rotation member 210.

If the first rotation member 210 revolves to the direction that the polishing sheet 200 wound around the second rotation member 220 is wound again, it means that the used polishing sheet 200 is wound again and it is not desirable.

Accordingly, the first rotation member 210 is coupled with a ratchet mechanism for limiting the first rotation member 210 to revolve to the direction that the polishing sheet 200 wound around the second rotation member 220 is released.

As the ratchet mechanism, the first rotation member 210 has a first gear 218 revolving therewith integrally and the first gear 218 is engaged with a second gear 228.

The second gear 228 has a pawl 2288 on its bottom surface and a ratchet gear 268 corresponding to the pawl 2288 is arranged around the second shaft member 420 on the inner face of the case member 100 as shown in FIG. 5.

The second gear 228 is mounted on the second shaft member 420 and engaged in the first gear 218.

The second gear 228 has a protrusion 2285 in its upper part and the second rotation member 220 has a centered through hole 2280 so that the protrusion 2285 of the second gear 228 is inserted into the centered through hole 2280 of the second rotation member 220.

In this embodiment, the protrusion 2285 of the second gear 228 includes a plurality of vertical members 22855 spaced each other along the circumferential direction.

Accordingly, when one revolves the rotation handle 80 and the first rotation member 210 rotates, only the counter-clockwise revolution in the drawing is possible and the revolution is possible only to the direction that the polishing sheet 200 wound around the second rotation member 220 is released.

When one revolves the rotation handle 80, the first rotation member 210 rotates with the first gear 218 and the second gear 228 engaged in the first gear 218 limits the rotation direction as the ratchet and prohibits the rotation to the direction that the polishing sheet 200 wound around the second rotation member 220 is wound.

Accordingly, if the rotation direction of the rotation handle 80 is to the direction that the polishing sheet 200 released from the second rotation member 220 is wound (clockwise direction in the drawing), the rotation of the rotation handle 80 is prohibited and if it is to the direction that polishing sheet 200 is released to the contrary (counter-clockwise direction in the drawing), the rotation handle 80 is allowed to revolve and the first rotation member 210 revolves and the polishing sheet 200 wound the second rotation member 220 is released and extends in a way that it is discharged out through the opening 80 as it is supported by the support portion 1016 and contacts the cushion member 70 and goes into the passage slot 180 and then it is wound around the first rotation member 210.

The polishing sheet 200 according to the present invention is the sheet having a fabric or a sponge and polishing particles adhered to the fabric or the sponge by means of the adhesive or glue. For example, a polishing sheet manufactured according to a sheet for trimming nails and method for producing the same (Patent No. 10-0558076) can be used.

FIG. 7 shows how to use the nail polishing device 1000 according to the embodiment of the present invention.

The cushion member 70 is disposed at the space 170 between the first lower surface part 101 and the third lower surface part 103 and the polishing sheet 200 c released from the second revolution member 220 is placed as it contacts the cushion member 70.

At this state, the nail is rubbed with the polishing sheet 200 c and is polished.

If the polishing particles of the polishing sheet 200 c are worn out, the rotation handle 80 is rotated so that the used part is wound to the first rotation member 210 through the passage slot 180 and new part is released from the second rotation member 220 and discharged to the space 180 and can be used.

When the whole parts of the polishing sheet 200 are all used, the case member is disassembled and the used polishing sheet 200 mounted on through the rotation members 210 and 220 is removed and replaced by new one.

As such, the present invention provides the nail polishing device 1000 in which the polishing sheet is partly discharged to be used and the polishing sheet can be replaced by new one after the whole parts of the polishing sheet are all used.

According to the present invention, the space 170 recessed at the lower surface of the case member 100 is formed, the cushion member 70 is disposed on the space 170 and the discharged part of the polishing sheet 200 c is extended to contact the cushion member 70. When one holds the case member 100 and rubs the nail with the partly discharged polishing sheet 200 c, the polishing sheet 200 c stably polishes the nail because the discharged polishing sheet 200 c is seated on the cushion member 70 at the space 170.

Also, the polishing sheet 200 c is stably stayed because of the friction with the cushion member 70 and it is possible to polish softly because of the cushion from the cushion member 70.

Further, the rotation handle revolves to the only one direction and the released polishing sheet cannot be wound. Especially, the present invention provides two gears and accomplishes such a function and the rotation member around which the polishing sheet is wound is mounted on the gear on which the ratchet is equipped. Accordingly, space is used efficiently.

FIG. 8 shows another embodiment of the holder member 60. In this case, the holder member 60 has a projection part 691 on its front face and, correspondingly, a groove 698 is formed on the lower surface of the case member 100. When the holding member 60 is closed, the projection part 691 moves to press the polishing sheet 200 c and is put into the groove 698 on the lower surface of the case member 100 so that the holder member 60 holds the polishing sheet more firmly.

With reference to FIGS. 9 to 13, on the centered through hole 2280 of the second rotation member 220, a third gear 224 is mounted.

The third gear 224 has teeth along the circumferential direction and a plurality of vertical parts 2245 extended vertically and spaced each other along the circumferential direction on the bottom surface. The vertical parts 2245 are inserted into the centered through hole 2280 of the second rotation member 220. The vertical parts 2245 spaced each other along the circumferential direction on the bottom surface of the third gear 224 are arranged in between the vertical members 22855 of the second gear 2280 spaced each other. Accordingly, the rotation of the third gear 224 and the rotation of the second gear 228 are integrally connected with each other.

Also, the holder member 60 has an extension part 684 extended towards the third gear 224 and at the end of the extension part 684, a corresponding part 6844 is formed which corresponds to the shape of the teeth of the third gear 224 so that when the holder member 60 rotates to close the opening 88 of the case member 100, the corresponding part 6844 correspondingly engages with the teeth of the third gear 224.

Accordingly, when the holder member 60 rotates to close the opening 88 of the case member 100, the projection part 691 of the holding member 60 presses the polishing sheet 200 c and is put into the groove 698 on the lower surface of the case member 100, and the corresponding part 6844 at the end of the extension part 684 holds the third gear 224.

In this case, especially with reference to FIG. 13, if the third gear 224 is tried to rotate to clockwise direction in the drawing, it forces the projection part 691 of the holding member 60 to be put into the groove 698 more and, as a result, the third gear 224 cannot rotate to clockwise direction and the second gear 228 integrally connected therewith cannot rotate to clockwise direction either.

Meanwhile, the second gear 228 cannot rotate to the counter-clockwise direction by the work of the ratchet as described above.

Accordingly, the first rotation member 210 connected with the second gear 228 through the first gear 218 cannot revolve either of clockwise direction or counter-clockwise direction.

As a result, if the holding member 60 rotates to close the opening part 88 of the case member, the projection part 691 thereof puts into the groove 698 on the lower surface of the case member and the corresponding part 6844 at the end of the extension part 684 holds the third gear 224 so that the first rotation member 210 is firmly locked and the polishing sheet 200 c released and discharged out is more firmly fixed without shake.

The user places the discharged polishing sheet 200 c on the nail or toenail and rubs it and during the time the polishing sheet 200 c stays the right position. Accordingly, the user can stably polish the nails or toenails.

As described, the present invention provides the nail polishing device in which a part of the polishing sheet is discharged and used, and a new part of the polishing sheet is newly discharged out and used after the discharged part of the polishing sheet is used and when all parts of the polishing sheet are used, it can be replaced by new one.

Also, the present invention disposes the cushion member on the lower surface of the case member and the partly discharged polishing sheet contacts the cushion member as it is extended. The partly discharged polishing sheet is stably seated on the cushion member so that when holding the case member and rubbing the nail with the polishing sheet, the polishing sheet stably polishes the nail. Also, the polishing sheet is stably stayed at the cushion sheet because of the friction therewith and the soft polishing is possible because of the cushion from the cushion member.

Further, according to the present invention, the rotation handle is limited to rotate to one direction and the released polishing sheet is not wound again. This function is accomplished with two gears connected with each other. Especially, the rotation member around which the polishing sheet is wound is mounted on the gear on which the ratchet is equipped. Accordingly, space is used efficiently.

Further, the present invention provides the holder member holding the polishing sheet. The holder member has the projection part on its front face and the case member has the groove on its lower surface with which the projection part is engaged. When the holder member moves to close, the projection part is engaged with the groove and holds the polishing sheet more firmly.

Furthermore, according to the present invention, the holder member holds the rotation member around which the polishing sheet is wound and when the holder member is closed, the polishing sheet is held not to move so that the user can stably polish the nail or toenail. Eventually, according to the present invention, the user can use the polishing sheet as much as it is used by discharging it as much and replace it by new one when the whole parts of the polishing sheet are all used, and stably polish the nail or toenail without shake. 

What is claimed is:
 1. A nail polishing device comprising: (a) a case member having an opening in its front and a passage slot on its lower surface; (b) a cushion member disposed on the lower surface of the case member and between the opening of the case member and the passage slot of the case member; (c) a polishing sheet wound around and through a first rotation member and a second rotation member inside of the case member, exposed to external around the opening and the passage slot of the case member and contacting the lower surface of the cushion member; (d) a rotation handle for rotating the first rotation member.
 2. The nail polishing device as claimed in claim 1 wherein the case member has two case members detachably assembled each other.
 3. The nail polishing device as claimed in claim 1 further comprising a holder member rotatably arranged at the opening of the case member to open or close the opening of the case member and having a projection part on its front face and a groove formed in front of the cushion member on the lower surface of the case member in which the projection part is engaged when the holding member rotates to close the opening of the case member.
 4. The nail polishing device as claimed in claim 3 wherein the lower surface of the case member recessed inwardly in its middle part to form space and the cushion member is disposed on the space.
 5. The nail polishing device as claimed in claim 4 further comprising a ratchet mechanism combined with the first rotation member for limiting rotation direction of the second rotation member to a direction that the polishing sheet is released, the ratchet mechanism including: (a) a first gear integrally rotating with the first rotation member; (b) a second gear engaged with the first gear and having a pawl on its bottom surface; (c) a ratchet gear corresponding to the pawl formed on inner face of the case member; wherein, (d) the second gear has a protrusion and the second rotation member has a centered through hole so that the protrusion of the second gear is inserted into the centered through hole of the second rotation member.
 6. The nail polishing device as claimed in claim 5 wherein the protrusion of the second gear has a plurality of vertical members spaced one other along circumferential direction.
 7. The nail polishing device as claimed in claim 6 further comprising a third gear having teeth along circumferential direction and a plurality of vertical parts extending downwardly and spaced one another along the circumferential direction; wherein, the vertical parts of the third gear is inserted into the centered through hole of the second rotation member and the vertical parts spaced one another on the bottom surface of the third gear are arranged in between the vertical members of the second gear spaced one another so that the rotation of the third gear and the rotation of the second gear are integrally connected with each other; and the holder member has an extension part extended towards the third gear and having a corresponding part corresponding to the shape of the teeth of the third gear at the end of the extension part so that when the holder member rotates to close the opening of the case member, the corresponding part correspondingly engages with the teeth of the third gear.
 8. The nail polishing device as claimed in claim 3 further comprising a ratchet mechanism combined with the first rotation member for limiting rotation direction of the second rotation member to a direction that the polishing sheet is released, the ratchet mechanism including: (a) a first gear integrally rotating with the first rotation member; (b) a second gear engaged with the first gear and having a pawl on its bottom surface; (c) a ratchet gear corresponding to the pawl formed on inner face of the case member; wherein, (d) the second gear has a protrusion and the second rotation member has a centered through hole so that the protrusion of the second gear is inserted into the centered through hole of the second rotation member.
 9. The nail polishing device as claimed in claim 8 wherein the protrusion of the second gear has a plurality of vertical members spaced one other along circumferential direction.
 10. The nail polishing device as claimed in claim 9 further comprising a third gear having teeth along circumferential direction and a plurality of vertical parts extending downwardly and spaced one another along the circumferential direction; wherein, the vertical parts of the third gear is inserted into the centered through hole of the second rotation member and the vertical parts spaced one another on the bottom surface of the third gear are arranged in between the vertical members of the second gear spaced one another so that the rotation of the third gear and the rotation of the second gear are integrally connected with each other; and the holder member has an extension part extended towards the third gear and having a corresponding part corresponding to the shape of the teeth of the third gear at the end of the extension part so that when the holder member rotates to close the opening of the case member, the corresponding part correspondingly engages with the teeth of the third gear. 